Bump phpstan/phpstan from 2.1.30 to 2.1.31

---
updated-dependencies:
- dependency-name: phpstan/phpstan
  dependency-version: 2.1.31
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]